Well maybe this could be interesting for you.
This is a video showing my 10s1p A123 + jazz55 + Neu 1515/2Y setup compared to a 6s2p A123 + MGM 16018 + Neu 1515/1Y setup. Both truggys do wheigh around 11lbs. The truggy with 6s2p used a 1.4sek ramp up time. Nonetheless he could easely keep up with the very "brutal" ramp up time of the Jazz. The 6s2p setup is slightly faster due to higher rpms and gearing choice.
Temperature of both motors were about the same at the end of the run (60 degree C). The 1Y was finned and passively cooled, the 2Y a smooth can with 2 small fans. Eventhough i used 2 cells less, my runtime was slightly higher. I personally would go with the HV setup. But either way you will have more then enough power for your fantastic built.